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When to Plant Radicchio in Elmore County, ID

Elmore County, Idaho Zone 7a May

May to-do list for Elmore County, Idaho

Each item below is timed to Elmore County, Idaho's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost April 27
Avg. first frost October 14
Soil temp (4") 47°F
Watering High
Pest pressure Low
Daylight 14.5 hrs
Before June arrives, get these ready
  • Starting indoors: radicchio
  • First harvests: radicchio

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Radicchio is an Italian chicory with stunning red and white leaves and a pleasantly bitter flavor. It forms tight heads and is used in salads, grilled, or braised.

Elmore County, Idaho is in USDA Zone 7a. The average last spring frost is April 27 and the first fall frost is October 14, giving you a growing season of approximately 170 days.

At an elevation of 5,944 feet, Elmore County receives approximately 20.3 inches of rainfall annually with predominantly loam soil. Summer highs average 88°F, providing good warmth for Radicchio during the growing season.

Elmore County, ID (Zone 7a) Moderate season
170 days
Last Spring Frost April 27
170 growing days
First Fall Frost October 14

Elmore County Soil Profile

Soil Type

Loam

Soil pH

6.7-8.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (78 days to spare)
Start indoors: Mar 10 Transplant: Apr 14 🍅 Harvest: Jun 16 – Jul 21
Recommended (50%) ✓ Fits season (72 days to spare)
Start indoors: Mar 23 Transplant: Apr 27 🍅 Harvest: Jun 29 – Aug 3
Safe Start (90%) ✓ Fits season (71 days to spare)
Start indoors: Apr 14 Transplant: May 19 🍅 Harvest: Jul 21 – Aug 25

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Soil Compatibility in Elmore County

How your county's soil matches Radicchio's growing requirements.

Soil pH

Your soil pH (6.7–8.3) is more alkaline than Radicchio prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Elmore County is excellent for Radicchio — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Radicchio.

Organic Matter

Organic matter is moderate (2.7%). Annual compost additions will help Radicchio.

How to Plant Radicchio

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Radicchio

3
successive plantings in your 170-day season

Sow every 6.9 weeks. Last sowing by Jul 26 to harvest before frost.

For a dedicated fall crop, sow by Aug 05.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
0.5″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 742 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Radicchio

Radicchio needs approximately 0.7 inches of water per week (3" per month). Here's how your county's rainfall compares month by month.

Month Radicchio Needs Rainfall You Supplement Action
Jan 1.6" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 1.7" 0" ❄️ Dormant
Apr 3" 1.9" 1.1" 💧 Light watering
May 3" 2.7" 0.3" 💧 Light watering
Jun 3" 1.6" 1.4" 💧 Light watering
Jul 3" 1.6" 1.4" 💧 Light watering
Aug 3" 1.9" 1.1" 💧 Light watering
Sep 3" 1.6" 1.4" 💧 Light watering
Oct 3" 1.7" 1.3" 💧 Light watering
Nov 1.4" 0" ❄️ Dormant
Dec 1.2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Elmore County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Radicchio Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Radicchio needs ~1,120 GDD — county provides 2,720 GDD Excellent fit

Radicchio Planting Timeline — Elmore County, ID

Radicchio Planting Calendar

Activity When Date Range
Start Indoors March 23 Mar 23 – Apr 6
Transplant Outdoors April 27 Apr 27 – May 11
Direct Sow April 13 Apr 13 – May 4
Harvest June 29 Jun 29 – Aug 3
Fall Sowing August 5 Aug 5 – Aug 19

Plant 0.5" deep · 6" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors Transplant Outdoors Direct Sow
May Transplant Outdoors Direct Sow
June Harvest
July Harvest
August Fall Sowing Harvest
September
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.7"/week · 1-2 times/week

📅 Days to Maturity

60–80 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 7a

📆 Growing Season

170 days in Elmore County

Growing Tips for Radicchio in Elmore County

Direct sow Radicchio outdoors after April 27 in Elmore County when soil has warmed and frost danger has passed.

Common pests for Radicchio in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

General growing tips

Start in late summer for fall harvest. The red color develops with cool nights and light frost. Harvest when heads are firm and compact.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Radicchio in Elmore County, ID?

Elmore County is in Zone 7a with an average last frost of April 27. Plan your Radicchio planting based on this frost date — see the calendar above for exact timing.

What planting zone is Elmore County, ID?

Elmore County, Idaho is in USDA Hardiness Zone 7a. The average last spring frost is April 27 and first fall frost is October 14.

🌱

Your Elmore County Garden Planner — Free

A 24-page printable planner built for Elmore County (Zone 7a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Elmore County, ID. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.